1. Field of the Invention
This invention relates to a shoulder belt anchor device used in a seatbelt system for restraining an occupant in an emergency situation of a vehicle, for engaging a shoulder webbing with a side wall of a vehicle body, and more particularly to a shoulder belt anchor device capable of moving a position of engagement.
2. Description of the Prior Art
Among various seatbelt systems, there is one having a shoulder webbing for obliquely restraining a shoulder of an occupant. In this seatbelt system, one end of this shoulder webbing is engaged with a vehicle body through an anchor device. With this anchor device, in order to reliably support a tension in the shoulder webbing generated by an inertial force of the occupant in an emergency situation of the vehicle to a side wall of a vehicle body, it is necessary to make this anchor device strong. From this reason, heretofore, an anchor plate for engaging one end portion of the shoulder webbing has been positively tightened to the side wall of the vehicle body.
However, this anchor device constitutes an anchor point which is an engaging portion of the shoulder webbing with the vehicle body, and this anchor point is a factor for determining a position of contact at the shoulder of the occupant. In consequence, this anchor point is determined such that a Proper webbing-fastened position is rendered to an occupant having an average physical build. However, the physical builds of the occupants are quite different from one occupant to another, from man to woman, and the position of the shoulder webbing being in contact with the occupant varies depending upon the driving posture of the occupant and changes in seat position.